1. Field of the Invention
The present invention relates to an imaging device such as a digital camera of card recording type.
2. Description of the Prior Art
A digital camera or an electronic camera includes an imaging device such as a charge coupled device (CCD). When shooting a subject with such a camera, an optical image of the subject is formed through an imaging lens system and is then converted by the imaging device into an image signal. The signal is thereafter transformed into digital image data to be recorded on a recording medium, for example, a memory card.
To record a frame of digital image data on a recording medium, about three to about four seconds are required when the data is not compressed. In general, the shooting operation is inhibited during the data recording operation. Therefore, most digital cameras are provided with an operation sequence in which when a shutter release button is depressed during the data recording, the shooting operation starts after the recording is completed. Consequently, a good shutter releasing chance is lost depending on cases.
To remove the problem, Japanese Patent Laid-Open Publication No. 6-86203 describes an electronic camera in which when a shutter release button is pressed during an image data recording operation, the data recording is temporarily interrupted. Thereafter, image signals are read from an imaging device and are then converted into digital image data to be once stored in a memory (shooting operation). After the shooting operation is finished, the recording of image data interrupted is restarted to record the data on a recording medium.
When the recording of one frame of image data on a recording medium is interrupted, part of image data of the frame is already recorded on the medium. When the recording operation is restarted after the shooting operation, remaining part of image data is recorded on the medium. However, the technology of the publication takes little account of compression of image data.
It is therefore an object of the present invention to provide an imaging apparatus in which when a shutter release button is pressed even during the compression of the image data obtained by shooting or the recording of the compressed image data on a recording medium, the shooting operation can be immediately started, and the image data obtained by the shooting can be compressed to be recorded on a recording medium after the shooting operation.
Another object of the present invention is to provide an imaging apparatus having a sequential or continuous image shooting function in which the continuous image shooting can be appropriately controlled.
In accordance with the present invention, there is provided an imaging apparatus including imaging means (an imaging device) for producing image data representing an optical image of an object, temporary storage means (a temporary storage device) for storing the image data attained from the imaging means, recording means (a recording device) for compressing one frame of image data stored in the temporary storage means and for writing the compressed image data on a recording medium, input means (an input device) for inputting an imaging instruction, and control means (a control device) for checking, while the recording means is compressing the image data and writing the compressed image data on the recording medium, to determine whether or not an imaging instruction is inputted from the input means, for controlling the recording means to interrupt the compression and write operation if an imaging instruction is inputted, and for storing the image data attained from the imaging means in the temporary storage means. After the image data from the imaging means is stored in the temporary storage means, a check is made to determine whether or not an imaging instruction is inputted from the input means. If an imaging instruction is not inputted, the data compression and the writing of image data on the recording medium are conducted for the frame of the image data stored in the temporary storage beginning always at a first point of the frame.
In accordance with the present invention, when a photographing instruction is inputted while the image data stored in the temporary storage means is being written through compression on a recording medium, the compression and write operation is immediately interrupted to initiate a photographing operation. Therefore, the user can photograph desired objects to obtain image data thereof without losing a good shutter releasing chance.
For image data which cannot be completely recorded on the medium due to the interruption of the write operation, a compression and write operation is carried out beginning at a start point of one frame of image data after the photographing is finished. The compression of one frame of image data and the recording of the compressed image data on the medium can be accomplished in a relatively short period of time, e.g., within one second. Consequently, even when one frame of image data is written on the medium beginning at the first portion thereof, the recording operation can be completed at once.
In accordance with the present invention, there is provided an imaging apparatus having a continuous shooting (shot) or photographing function including imaging means (an imaging device) for producing image data representing an optical image of an object, temporary storage means (a temporary storage device) having a storage capacity of storing a plurality of frames of image data for storing the image data attained from the imaging means, recording means (a recording device) for compressing one frame of image data stored in the temporary storage means and for writing the compressed image data on a recording medium, input means (an input device) for inputting an imaging instruction, and continuous shot control means (a continuous shot control device) for conducting, as long as an input instruction is inputted from the input means, a control operation to repeatedly achieve the storage operation of the image data from the imaging means in the temporary storage means. When the image data stored in the temporary storage means reaches a maximum storable amount of the temporary storage means or when the sum of the image data stored in the temporary storage means and the image data already recorded on the recording medium reaches a maximum storable amount of the recording medium, the sequential shot control means inhibits a photographing operation.
In accordance with the present invention, the continuous photographing operation is controlled in consideration of the number of frames already photographed and stored in the temporary storage means and on the recording medium and the number of frames recordable on the medium. In consequence, all image data produced by the photographing can be stored on the recording medium without overflow of data.
In accordance with one embodiment of the present invention, the imaging apparatus further includes display means (a display device) for displaying the storable amount of the temporary storage means as a number of frames for continuous shot. The display means restricts the number of frames for continuous shot in accordance with a recordable amount of the recording medium, the recordable amount remaining in the recording medium if the image data stored in the temporary storage means is recorded on the recording medium.
The sequential or continuous photographing is possible within the recording capacity of the recording medium. The number of recordable frames is appropriately displayed for the continuous photographing.